草牧场防护林带对牧草质量和草场生产力影响的评价

草牧场防护林对牧草质量和草场生产力的影响是评价草牧场防护林效益的关键。本文在分析草场土壤背景值的基础上,分别对牧草营养期和绿果期,用牧草营养物质含量和能量指标评价了4年生白城杨(Populux×xiaozuanica)林带对几种主要牧草质量的影响。用牧草生物量和单位面积能量评价林带对草场生产力的影响。结果表明:营养期的牧草磷和粗蛋白含量分别提高0.012％和1.365％,无氮浸出物含量降低2.025％,牧草质量得到了改善;草场生物量和能量分别增加131.5kg/ha和741.4MJ/ha,提高了草场生产力。绿果期的牧草磷、粗蛋白、无氮浸出物和粗纤维含量与林带的存在无关、各草种粗脂肪的加权平均含量明显降低(降低值为0.634％),说明林带对牧草质量产生不良影响。但单位重牧草能量增加了0.175MJ/kg,使单位面积牧草能量提高634MJ/ha。各草种单位重能量加权平构值在10H和15H处较大,与林网内净辐射量较大位置相一致。

ESTIMATION OF INFLUENCE OF PROTECTION FOREST FOR PASTURE ON GRASS QUALITY AND GRASSLAND PRODUCTIVITY

The effect of protection forest for pasture on grass quality and grassland productivity is the key for estimating its function. The influence of 4 year old populus x xiaozuanica forest belt, on the quality of main grass species were estimated with nutrient matter content and energy of grass in nutritive and greenfruit periods, on grassland productivity were estimated by grass biomass and unit area energy except the soil background value. The results show that P and crude protein content in nutritive grass increased 0.012%, 1.365% respectively, nonitrogen component reduced 2.025%, the grass quality have been improved. Biomass and energy of grassland increased 131.5kg/ha,741.4MJ/ha, the productivity improved. Ths content of P, crude protein, no-nit-rogen component and crude fibre in greenfruit period have on relation with forest belt. Weighed average content of crude fat in grass reduced (0.634%) obviously, which describes the belt has on good effect on grass quality, unit weight grass energy increased 0.175MJ/kg, unit area 634MJ/ha. The average value of unit weight energy is much great at 10H and 15H, that is the position of great net radiation.